List Out All <type> of Visitor Activity object #176

On the Object Field References page under Visitor Activity, after type 34 it says Unknown. However, there are types that get returned beyond that as well. Specifically, type 35, 36, and 37 for indirect unsubscribes, indirect bounce, and indirect opt in. Might be helpful to list those out and clarify that type 12, 13, and 16 are direct.